Aeration device

ABSTRACT

A soil aeration device may include a plurality of arcuate blades mounted to an assembly adapted to rotate and translate the blades proximate a ground surface, thereby forming aeration pockets in the soil. In certain embodiments, the arcuate tines penetrate and fracture the soil while minimizing the amount of soil lifted from the pocket deposited on the top of the soil. In various embodiments, a planetary gear assembly imparts to the tine a translational and rotational movement which creates a fractured pocket in the soil while minimizing the amount of soil lifted from the pocket and deposited on the surface of the soil. In still other embodiments, the arcuate tine may have mounted thereon a coring tube that cuts and removes a plug from the pocket formed in the soil.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 11/318,728(now U.S. Pat. No. 7,669,666) entitled “Aeration Device” and filed byDavid R. Maas et al. on Dec. 27, 2005, which (1) is acontinuation-in-part of U.S. application Ser. No. 10/387,092 (now U.S.Pat. No. 7,096,968) entitled “Aeration Device” and filed on Mar. 12,2003, which claims priority to U.S. Provisional Application No.60/363,786 entitled “Aeration Device” and filed on Mar. 12, 2002, and(2) is also a continuation-in-part of U.S. patent application Ser. No.10/775,998 (now U.S. Pat. No. 6,983,806) entitled “Aeration Device” andfiled on Feb. 10, 2004, which is a continuation of U.S. patentapplication Ser. No. 10/281,786 (now U.S. Pat. No. 6,691,791) entitled“Soil Aeration Tine” and filed on Oct. 28, 2002, which is a divisionalof U.S. patent application Ser. No. 09/821,373 (now U.S. Pat. No.6,513,603) entitled “Soil Aeration Tine” and filed on Mar. 29, 2001. Theentireties of these applications are incorporated herein by reference.

BACKGROUND

Soil aeration devices are generally designed to cut a plug out of thesoil instead of driving a spike into the soil because the latterapproach compacts the soil. Towable soil aerator devices typicallyremove plugs of soil while forming an enlarged soil aeration pocket.Such aerators include hollow cylindrical tubes that enter the soil at anangle to cut free a cylindrical soil plug which contains grass, grassroots and soil. As the soil aeration device moves forward, planetarygears in the soil aeration device cause the soil aeration tubes to pivotto form a soil aeration hole or pocket wherein the bottom portion of thesoil aeration hole is larger than the top opening of the soil aerationhole. The soil aeration tube is then lifted out of the soil to removethe soil plug, which is usually discarded on top of the soil.

One of the difficulties with soil aeration devices is that a substantialamount of soil, grass and roots in the form of cylindrical plugs areleft on top of the soil. These soil plugs must either be removed,allowed to decompose, or pulverized via mowing. Generally, the largerthe soil plugs, the longer it takes for the soil plugs to decomposenaturally.

SUMMARY

A soil aeration device may include a plurality of arcuate blades mountedto an assembly adapted to rotate and translate the blades proximate aground surface, thereby forming aeration pockets in the soil. In certainembodiments, the arcuate tines penetrate and fracture the soil whileminimizing the amount of soil lifted from the pocket deposited on thetop of the soil. In various embodiments, a planetary gear assemblyimparts to the tine a translational and rotational movement whichcreates a fractured pocket in the soil while minimizing the amount ofsoil lifted from the pocket and deposited on the surface of the soil. Instill other embodiments, the arcuate tine may have mounted thereon acoring tube that cuts and removes a plug from the pocket formed in thesoil.

The apparatus described herein may provide one or more of the followingadvantages. In certain embodiments, the soil aeration device enables agrassy area such as a golf course fairway to be aerated without thedeposition of the plugs or significant amounts of soil on the grass,thereby permitting use of the fairway immediately after aeration withoutthe need to remove or mow soil plugs or otherwise treat the area. Insome embodiments, the translational and rotational movement imparted toan arcuate coring tine minimizes the size of the aperture cut in thesoil and the amount of soil lifted from the aeration pocket anddeposited on the surface of the ground.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages of the invention will be apparent from the description anddrawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a soil aerator device having a set ofaeration tines.

FIG. 2 is a top view of an aeration tine.

FIG. 3 is a side view of the aeration tine of FIG. 2.

FIG. 3 a is a front view of the aeration tine of FIG. 2.

FIG. 3 b is a back view of the aeration tine of FIG. 2.

FIG. 4 is a bottom view of the aeration tine of FIG. 2.

FIG. 5 is a partial side view showing the aeration tine of FIG. 2penetrating the soil.

FIG. 6 is a partial side view showing the aeration tine of FIG. 2partially rotated within the soil.

FIG. 7 is a partial side view showing the aeration tine of FIG. 2emerging from the soil.

FIG. 8 is a perspective view of an alternate aeration tine.

FIG. 9 is a top view of the aeration tine of FIG. 8.

FIG. 10 is an end view of the aeration tine of FIG. 8.

FIG. 11 is a side view of the aeration tine of FIG. 8.

FIG. 12 is a perspective view of yet another embodiment of an aerationtine.

FIG. 13 is a top view of the aeration tine of FIG. 12.

FIG. 14 is an end view of the aeration tine of FIG. 12.

FIG. 15 is a side view of the aeration tine of FIG. 12.

FIG. 16 is a perspective view of an aeration tine adapted for use onputting greens.

FIG. 17 is a top view of the aeration tine of FIG. 16;

FIG. 18 is an end view of the aeration tine of FIG. 16;

FIG. 19 is a side view of the aeration tine of FIG. 16;

FIG. 20 depicts a golf course green that has been aerated with theaeration tine of FIG. 16.

FIGS. 21-24 depict the planetary motion of arcuate tines in certainembodiments.

FIGS. 25-26 depict a top view and a side view, respectively, of anotherembodiment of an aeration tine.

FIG. 27 is a side view of a portion of an aeration device in accordancewith some embodiments.

FIGS. 28-29 depict the planetary motion of arcuate tines in certainembodiments.

FIGS. 30-31 depict the planetary motion of arcuate tines in somealternative embodiments.

FIGS. 32-33 are side views of a portion of an aeration device inaccordance with some embodiments.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a pull type soil aeration device 10having a frame 11 supported by a pair of wheels 12. A gear mechanism 13,which is connected to the power take off shaft of a tractor (not shown),rotates the tine holders 14 which contain a set of soil aeration tines15. In the embodiment shown the aeration tines are located on parallelmembers and rotate in an epicycle or planetary manner. A soil aerationdevice providing planetary motion is more fully described in Bjorge U.S.Pat. No. 5,469,922 titled Soil Aerator issued Nov. 28, 1995 and isincorporated herein by reference.

FIG. 2 shows a top view of soil aeration tine 15 capable of bothfracturing and removing soil. Soil aeration tine 15 comprises anelongated member 20 having a central axis 19. Elongated member 20 has afirst section 22 terminating in an apex end 23 and a second section ormounting end 21 for mounting elongated member 20 on a soil aerationdevice. Mounted to elongated member 20 is a cylindrical soil cuttingtube 25 which is positioned rearwardly or aft of apex end 23 so thatwhen apex end 23 of elongated member 20 is axially driven into a patchof soil the apex end 23 of elongated member 20 penetrates the patch ofsoil before the soil cutting tube 25 engages the soil. As the firstsection 22 penetrates the soil it fractures the soil to form a partialsoil aeration pocket. Next, the soil 20 cutting tube 25 which ispositioned axially rearwardly of the apex 23 and has an annular cuttingedge 25 c and a conically tapered surface 25 a engages the soil aft ofthe apex end and proximate the soil aeration tine 15 to cut a plug ofthe soil free of the soil. Thus the fracturing of the soil occurs in thesoil around the lower portion of the hole and both fracturing and soilremoval occurs in the soil zone proximate the cutting tube which resultsin a soil aeration pocket in the soil where the soil aeration pocket islarger than the soil plug cut free of the soil and also without the soilcompaction that would occur if a spike were driven downward into thesoil.

FIG. 3 shows a side view of soil aeration tine 20 illustrating a portionof a divergent soil fracturing section 22 which includes an upwardlycurving soil fracturing face 20 a and an upwardly curving soilfracturing face 20 b that terminates at apex end 23. FIG. 3 a shows theopposite side of soil aeration tine 15 illustrating the other side ofthe divergent soil fracturing section 22 which includes identicalupwardly curving soil fracturing faces 20 c and 20 d that terminates atapex end 23. A soil lifting face 24 extends laterally from side-to sideof soil aeration tine 15. The soil lifting face 24 forms a scoop orspade so that when the soil aeration tine is rotationally removed fromthe soil the soil face 24 can lift or scoop soil from the soil aerationpocket.

The soil cutting tube 25 has a leading and annular cutting edge 25 cthat diverges outwardly along annular face 25 a to the cylindricalshaped soil cutting tube 25. The cutting edge 25 c of cutting tube 25 ispositioned a distance L rearward of the apex end 23 of soil aerationtine 15 to enable the soil fracturing section 22 to penetrate andfracture the soil before the soil aeration tube cuts a soil plug free ofthe soil. In the embodiment shown the soil cutting tube is positioned atleast one and one half inches rearward of the apex end to ensure thatthe length of the soil plug is kept to a minimum. On the other hand thesoil cutting tube should extend sufficiently far along elongated member20 so as to ensure that one can cut through the top layer of grass andsoil. Thus, in the embodiment shown in the drawings the end of the tine15 lacks an end coring device.

FIG. 3 b shows a back view of soil aeration tine 15 with a first line 31extending outward from the central axis 19 of elongated member 20 and asecond line 30 extending outward from the geometric center of cuttingtube 25 with the distance between the centers indicated by the dimensionx. That is, FIG. 3 b illustrates that the cutting tube is laterallyoffset from the elongated member 20 so that cutting tube 20 andelongated member 20 enter the soil in a side by side condition.

FIG. 4 is a bottom view of soil aeration tine 15 illustrating that thesoil fracturing faces 20 a and 20 c extend axially along elongatedmember 20 and terminate at apex end 23. Thus the under side of aerationtine 15 presents soil fracturing surfaces 20 a and 20 c while the topside of soil aeration tine 15 presents the latterly offset andrearwardly positioned cutting tube 25 for cutting the soil to remove aplug of soil and grass.

FIG. 5 is a partial schematic illustrating how soil aeration tine 15penetrates a patch of soil 40 at an acute angle φ with respect to thetop soil. In the first step the soil aeration soil fracturing surfaces20 a, 20 b on one side of elongated member 20 and the soil fracturingsurfaces 20 c and 20 d located on the opposite side of the elongatedmember penetrate the soil with the soil fracturing surfaces entering thesoil at an acute angle causing the soil 15 proximate the soil aerationtine 15 to fracture upward rather than compact. That is the acute anglepenetration of the soil fracturing surfaces with the fracturing surfacesfacing upward produces an upward component that forces the soil upward.As the soil can fracture and move upward the resistance to soilcompaction above the soil aeration tine 15 is less than the resistanceto soil compaction in the lateral direction. That is, lateral displacingsoil produces increased soil compaction since the soil must compactagainst itself. Thus avoiding direct lateral compaction inhibits soilcompaction. At the same tine the soil fracturing faces fracture theportion of the soil located ahead of the soil aeration tine the cuttingedge 25 c, which trails the apex end 23, cuts a soil plug free of thesoil. In the embodiment shown the cutting edge 25 c extendssubstantially perpendicular to soil aeration tine 15 to enable the soilaeration tube 25 to capture a soil plug aft of the apex end 23 as thesoil aeration tine 15 is driven axially into the soil. It should bepointed out that although multiple soil fracturing faces are shown it isenvisioned that only a single soil fracturing surface could be used.

FIG. 6 illustrates the step when the soil aeration tine is rotated in aclockwise direction as the tine is being moved forward. This rotationalaction results in an aeration pocket 41 being formed in the region firstpenetrated by the soil aeration tine.

FIG. 7 illustrates the further enlargement of the soil aeration pocket41 as the soil aeration tine 15 continues in a compound motion as aresult of the planetary action that drives the tine rearward during therotation of the support mechanism and forward due to the pulling of thesoil aeration device and the rotation of the aeration tine. As a result,the compound rotation causes the soil aeration tine top face 24 to liftor scoop soil from the aeration pocket while a cut soil plug 42 is heldin cutting tube 25 to be disposed of on the ground when the soilaeration tube 15 exits the soil. The result is that one can form a soilaeration pocket 41 with a minimum of soil compaction and a minimum ofdisplaced soil as the soil aeration tine with the aft cutting tuberemoves a soil plug of substantially smaller volume than a soil aerationtube located on an apex end of a soil aeration tube. Consequently, lesssoil is left on top of the soil since the soil plugs formed by thepresent method are smaller than soil plugs formed by the end coremethod. Yet at the same tine the aeration holes 41 formed in the soilare as large or larger than holes formed by a conventional cylindricalcutting tubes.

Thus the method of making a soil aeration hole 41 comprises the step ofextending an elongated member 20 having a lateral face 24 on one sideand a soil diverging section formed by faces 20 a and 20 c on the otherside into the soil to fracture the soil proximate the diverging faces.In addition, one cuts a soil plug free of the soil with the soilaeration tube 25 by cutting the soil plug from the soil located rearwardand lateral of the diverging faces 20 and 20 c. By rotationally removingthe elongated member 20 one can free the soil plug and form a soilaeration hole 41 having a top opening smaller than a bottom opening asshown in FIG. 7. Also by rotationally removing the elongated member 20with the apex end 23 and lifting surface 24 one can partially scoop outsoil with the soil lifting face 24 on the elongated member.

In the embodiments shown the soil cutting tube 25 has an externaldiameter larger than the external diameter of the aerator tine.Although, it is submitted that the diameter of the soil cutting tube 25can be governed by other factors such as soil types and soil conditions.

Thus the soil aerator tine 15 can include at least one soil fracturingface in a diverging section 22 which diverges in a direction rearwardfrom an apex end 23 on soil aerator tine 15 and in a direction away froma lifting face 24 on soil aerator tine 15. The soil aeration device 15illustrated in FIG. 3 a shows two soil fracturing faces 20 a and 20 csymmetrically positioned around a central axis 19 extending through thesoil aeration tine elongated member 20. A review of FIG. 3 a shows thatapex end 23 on soil aeration tube 22 is located lateral of the centralaxis 19 extending through the soil aeration tube 15. By having the soildiverging faces forming an off center apex 23 on one side of the soilaeration tine 15 the soil against the soil face 24 is penetrated withoutcompaction while the soil above the soil aeration fracture faces isforced away from the soil aeration tube. When the soil aeration tube isdriven at an acute angle into the soil the diverging fracturing surfacesmove the soil upward which fractures the soil without compacting thesoil.

FIGS. 8-11 depict an aeration blade 80 adapted for use in connectionwith the above-described aeration device 10. The blade 80 functionssimilarly to the aeration tine 15 discussed above, except that it doesnot cut and remove a plug of soil. The arcuate tine 80 penetrates thesoil as shown and described in connection with FIGS. 5-7, but becausethis blade lacks the soil cutting tube 25, no plug is removed from thesoil and deposited on the surface of the aerated turf. Rather, as theaeration tine 80 pivots in the motion shown in FIGS. 5-7, the arcuateend 81 of the aeration tine 80 cuts an aeration groove having a longerdimension in the direction of the cut, which provides a degree ofaeration comparable to that provided by aeration tine 15.

Moreover, turf aerated with tine 80 will not be littered with aerationplugs. As shown in FIG. 20, the surface 200 of the aerated turf remainssubstantially uniform. The aeration pockets 201 are visible, but nosignificant amount of soil has been deposited on the grass surface 200.Accordingly, the turf need not be further treated (as by mowing) beforereceiving approach shots or serving as a putting surface. The aerationtine 80 can thus be advantageously implemented to significantly reducemaintenance expenditures and virtually eliminate course downtime causedby aeration procedures.

Returning to FIGS. 8-11, the aeration blade 80 has a tip 82, concaveedge 83, and convex edge 84. The cavity 85 is adapted to be receivedonto a mounting element (not shown) protruding from tine holders 14 ofthe soil aeration device 10. The blade 80 may be made of high strengthsteel, metal alloys, composites, hard polymeric materials, or othersuitable materials. The cavity 85 may include threads, keys, detents,cross-drilled tapped holes for set screws, or other suitable structurethat cooperates with the mounting elements on tine holders 14 tosecurely and releaseably hold blades 80. Releaseable mountingconfigurations advantageously facilitate removal of blades 80 forsharpening or replacement. The aeration tine 80 of FIGS. 8-11 has awidth 82 of approximately 7/16″.

The aeration tines of FIGS. 12-15 are similar to the tine of FIGS. 8-11,except that the tine of FIGS. 12-15 has a width 122 of approximately5/16″. The tine of FIGS. 16-19 has a width 162 of approximately ⅛″ andis adapted for aeration of surfaces which must remain particular flatand even after aeration, such as putting greens.

The operation of the arcuate aeration blades are shown in more detail inFIGS. 21-24. With reference to FIG. 21, an arcuate aeration blade 90penetrates soil 89 in a downward, clockwise motion 92. As the tractorproceeds in the direction shown by arrow 94, the planet gear (not shown)that drives the blade 90 rotates in clockwise direction (as shown byarrow 92) while being driven in a counterclockwise planetary direction(as indicated by arrow 91). As the tractor continues in the direction ofarrow 94, the blade 90 translates in the direction of arrow 91 whilecontinuing to rotate in the direction indicted by arrow 92, thus carvingan aeration pocket and causing soil fractures 93. Optionally, the blade90 can be mounted in the opposite direction, such that its longer bladeedge end faces in direction 94. Such an arrangement can be usefullyemployed to, for instance, lift soil from the aeration pocket, therebyincreasing the pocket's size.

FIGS. 23-24 depict an embodiment in which the planetary motion isreversed relative to that shown in FIGS. 21-22. The blade 98 plungesdownward into the soil 89 as it translates in the direction of arrow 96and rotates in a counter-clockwise direction, as indicated by arrow 97.As the tractor proceeds in the direction of arrow 95, the blade 98continues to translate and rotate in the aforementioned directions,thereby forming a pocket and soil fractures 99.

The blade 80 can be equipped with an aeration tube 25 on its trailing orleading edges, as shown in FIGS. 25-26. In such embodiments, the arcuateblade serves to fracture the soil which is compacted by the soilaeration tube 25.

Referring to FIG. 27, a soil aeration device 300 may operate to orientan arcuate aeration tine 390 (similar to the tine 90 described inconnection with FIGS. 21-24) so that a tip portion 395 penetrates theground surface 340 in a substantially vertical direction. In theseembodiments, such orientation of the arcuate aeration tine 390 mayreduce the stress and fatigue on components of the gear system 13, suchas the gears 13 a and 13 b and coupling members (e.g., chain members)described in connection with FIG. 1.

Similar to the embodiments previously described in connection with FIGS.1 and 21-24, the arcuate aeration tine 390 in the current embodiment isremovably mounted to tine holders 14 and rotate in an epicycle orplanetary motion (for purposes of clarity only one tine 390 is shown inFIG. 27). For example, in this embodiment, the power take off shaft of atractor drives the carrier 18 to rotate in a counter-clockwise directionabout the central axis 305 (while the sun gear 13 b remainssubstantially stationary relative to the central axis 305), therebycausing the planet gears 13 a to revolve 391 about the central axis 305.In response to the revolving motion 391, the sun gear 13 b compels eachof a plurality of planet gears 13 a to rotate about its own axis in aclockwise direction 392 due to one or more coupling members 16 (e.g.,chain members in this embodiment). The revolving motion 391 and therotating motion 392 are transmitted to the arcuate aeration tines 390because each tine rack 14 (refer, for example, to FIG. 1) undergoes thesame compound motions 391 and 392 as the corresponding planet gear 13 a.By properly timing the revolving motion 391 and the rotational motion392 of the planet gears 13 a the aeration device 300 is capable ofpositioning the arcuate aeration tines 390 so that the tip portions 395penetrate the ground surface 340 in a substantially verticalorientation.

Still referring to FIG. 27, in some embodiments, the planet gears 13 aare timed such that the arcuate aeration tines 390 initially penetratethe ground surface 340 when the epicycle orientation of the planet gear13 a relative to the central axis 305 is substantially at an acute angleA. Additionally, the tip portion 395 of the arcuate aeration tine 390may penetrate the ground surface 340 at a substantially vertical angle B(e.g., substantially perpendicular to the ground surface 340). In thisembodiment, for example, the tip portion 395 of the arcuate aerationtine 390 may penetrate the ground surface 340 when angle B isapproximately 75 degrees to approximately 105 degrees and may beapproximately 90 degrees. With angle B set in this range, it should beunderstood that the curvature of the tine 390 may affect the position ofthe mounting end of tine 390 (and the tine holder 14 and the planet gear13 a). As such, in these embodiments, the tip portion 395 of the tine390 may initially penetrate the ground surface when angle A isapproximately less than 45 degrees, may be approximately 5 degrees toapproximately 40 degrees, and may be approximately 30 degrees. Suchorientation of the arcuate aeration tine 390 may cause the tip portion395 to initially fracture the ground surface in an efficient manner,which may reduce the impact stress upon the gear system 13 (e.g., gears13 a and 13 b and coupling members 16).

Referring to FIG. 28, one embodiment of an arcuate aeration tine 390includes an arcuate blade portion having a concave edge 383 andcomplimentary convex edge 384 (similar to the concave edge 83 and theconvex edge 84 described in connection with FIGS. 8-11). At least one ofthe concave and convex faces 383 and 384 may be capable of fracturingthe soil when the arcuate aeration tine 390 penetrates the groundsurface 340. The arcuate aeration tine 390 may include a mountingdevice, such as a threaded cavity 385 to releasably mount onto athreaded stud (not shown in FIG. 28) on the tine rack 14. In thisembodiment, the tractor may pull the aeration device 300 over the groundsurface 340 in a substantially horizontal direction 394. As previouslydescribed, the revolving motion of the planet gear 13 a (FIG. 27) maycause the tine 390 to have a corresponding translational motion 391, andthe rotational motion of the planet gear 13 a may cause the tine 390 tohave a corresponding rotational motion 392. The planetary gear system 13may be configured to orient the tine 390 so that the tip portion 395penetrates the ground surface 340 in a substantially vertical direction(as described above). By penetrating the ground surface 340 in thisorientation, the impact energy upon the tine 390 (transmitted to thegear system) may be reduced.

Referring to FIG. 29, the translational and rotational motions 391 and392 of the tine 390 causes the arcuate aeration tine 390 to form anaeration pocket 341. In this embodiment, the tip portion 395 of thearcuate aeration tine 390 penetrates the ground surface 340 in asubstantially vertical direction, which may cause at least a portion ofa wall of the aeration pocket 341 to extend in a substantially verticaldirection. The convex edge 384 of the tine 390 may sweep through and cutthe soil during the rotational motion 392. The translational androtational motion 391 and 392 may cause the tip portion 395 of tine 390to exit the ground surface 340 with an orientation that is substantiallynon-vertical, thereby creating at least a portion of a second wall ofthe aeration pocket 341 that extends in a substantially non-verticaldirection. Thus, in some embodiments, the vertical entry of the tipportion 395 of the tine 390, combined with the rotational motion 392 ofthe tine 390 and the substantially non-vertical exit of the tip portion395, may cause the tine 390 to form a non-symmetric aeration pocket 341.

FIGS. 30-31 depict an embodiment in which the epicycle or planetarymotion is reversed relative to that shown in FIGS. 27-29. In thisembodiment, the tractor pulls the aeration device 300 over the groundsurface 340, in a substantially horizontal direction 398. As previouslydescribed, the revolving motion of the planet gear 13 a may cause thetine 390 to have a corresponding translational motion 396, and therotational motion of the planet gear 13 a may cause the tine 390 to havea corresponding rotational motion 397. The planetary gear system 13 maybe configured to orient the tine 390 so that the tip portion 395penetrates the ground surface 340 in a substantially vertical direction(as described above). For example, when the tine 390 penetrates theground surface 340, angle B may be approximately 75 degrees toapproximately 105 degrees and may be approximately 90 degrees. Bypenetrating the ground surface 340 in this orientation, the impactenergy upon the tine 398 (transmitted to the gear system) may bereduced.

Referring to FIG. 31, the translational and rotational motions 396 and397 of the tine 390 causes the tine 390 to form an aeration pocket 342.In this embodiment, the tip 395 of the arcuate aeration tine 390penetrates the ground surface 340 in a substantially vertical direction,which may cause at least a portion of a wall of the aeration pocket 342to extend in a substantially vertical direction. The convex edge 384 ofthe tine 390 may sweep through and cut the soil during the rotationalmotion 397. The translational and rotational motion 396 and 397 maycause the tip portion of the tine 390 to exit the ground surface 340with an orientation that is substantially non-vertical, thereby creatinga second wall of the aeration pocket 341 to extend at least partially ina substantially non-vertical direction. Similar to previously describedembodiments, the vertical entry of the tip portion 395 of the tine 390,combined with the rotational motion 397 of the tine 390 and thesubstantially non-vertical exit of the tip portion 395, may cause thetine 390 to form a non-symmetric aeration pocket 342.

It should be understood that, in some embodiments, the curved tine 390can be equipped with an aeration tube 25 on its trailing or leadingedges (refer, for example, to FIGS. 25-26). In such embodiments, thearcuate portion may fracture the soil which is compacted by the soilaeration tube 25.

Referring now to FIGS. 32-33, some embodiments of a soil aeration device400 may be equipped with an adjustable timing device 401 that permitsthe timing of the gear system 13 to be shifted. In particularembodiments, a user may adjust the timing device 401 from a firstposition to a second position, which in turn causes the gear system 13to shift the location and orientation of the aeration tines 490 wheninitially penetrating the ground surface 440. For example, as shown inFIG. 32, the user may select the position of the timing device 401 sothat the gear system 13 causes the tip portion of the aeration tines 490to penetrate the ground surface 440 in a substantially verticalorientation (previously described in connection with FIG. 27). Inanother example, as shown in FIG. 33, the user may adjust the positionof the timing device 401 so that the gear system 13 causes the tipportion of the aeration tines 490 to penetrate the ground surface 440 ina forward angular orientation.

Similar to the embodiments previously described in connection with FIGS.1 and 21-24, the arcuate aeration tine 490 in the current embodiment isremovably mounted to tine holders 14 and rotate in an epicycle orplanetary motion (for purposes of clarity only one tine 490 is shown inFIGS. 32-33) as a vehicle drives the aeration device 400 over the groundsurface 440 in a substantially horizontal, forward direction 494. Forexample, in this embodiment, the power take off shaft of a tractordrives the carrier 18 to rotate in a counter-clockwise direction aboutthe central axis 405 (while the sun gear 13 b remains substantiallystationary relative to the central axis 405 during operation), therebycausing the planet gears 13 a to revolve 491 about the central axis 405.In response to the revolving motion 491, the sun gear 13 b compels eachof a plurality of planet gears 13 a to rotate about its own axis in aclockwise direction 492 due to one or more coupling members 16 (e.g.,chain members in this embodiment). The revolving motion 491 and therotating motion 492 are transmitted to the arcuate aeration tines 490because each tine rack 14 (refer, for example, to FIG. 1) undergoes thesame compound motions 491 and 492 as the corresponding planet gear 13 a.By shifting the angular orientation of the sun gear 13 b relative to thecentral axis 405, timing of the gear system 13 can be adjusted so thatthe tip portion 495 of the aeration tine 490 penetrates the groundsurface 440 in one of a plurality of orientations.

The orientation and location of the aeration tine 490 (as the tipportion 495 penetrates the ground surface 440) may be adjusted dependingon the desired size of aeration pocket opening at the ground surface,the extent of aeration necessary for a particular patch of soil, and anumber of other factors. For example, as shown in FIG. 32, the user mayselect the position of the timing device 401 so that the gear system 13causes the tip portion 495 of the aeration tines 490 to penetrate theground surface 440 in a substantially vertical orientation (previouslydescribed in connection with FIG. 27). This tine penetration positionmay provide a smaller aeration pocket opening at the ground surface 440,and in some circumstances, may provide less surface disruption. As shownin FIG. 33, the user may adjust the position of the timing device 401 sothat the gear system 13 causes the tip portion 495 of the aeration tines490 to penetrate the ground surface 440 in a forward angularorientation. This forward angular orientation when the tine initiallypenetrates the ground may provide a longer slice downward at the groundsurface 440, thereby producing a large-sized opening at the groundsurface 440 or a continuous slit in the surface 440 from the penetrationof successive tines 490 (refer, for example, to FIG. 20 for a depictionof such continuous slits). Unlike other machines used to cut continuousslits in the ground, which employ a series of saw blades axially spacedapart on a simple rotating shaft, embodiments of the soil aerationdevice 400 (depicted in FIG. 33) may cut downward into the soil and donot necessarily scoop soil up from the ground with an upward facingconcave blade surface. Rather, embodiments the soil aeration device 400may form an aeration pocket or slit with the convex edge 484 leadingthrough the soil, and thus the leading convex edge 484 may exit theground surface 440 at the end of its cutting path (without scoopingsubstantial amounts of soil with a convex blade edge).

Still referring to FIGS. 32-33, the timing device 401 may include atiming arm that is mechanically coupled to the sun gear 13 b so as toadjust the angular orientation of the sun gear 13 b relative to thecentral axis 405. For example, the timing device 401 may include one ormore mounting holes 402 for receiving screws or other fasteners to mountthe timing device 401 to the sun gear 13 b. Also, in some embodiments,the timing device 401 may include an adapter portion 403 that isconfigured to receive a handle, a shaft, a cable, or other mechanism(not shown in FIGS. 32-33) for user control of the timing device 401. Assuch, a user may grasp or otherwise control a handle, a shaft, a cable,or other mechanism to adjust the timing device 401 from a first positionto a second position.

In some embodiments, the timing device 401 may be shifted from the firstposition to the second position using a key and key slot arrangement.For example, the timing device 401 may include a key member 404 thatextends outwardly from the timing device 401 to engage one of aplurality of mating key slots, with each key slot representing oneselectable position for the timing device 401. The key slots (not shownin FIGS. 32-33) may be coupled to or integrally formed in the frame ofthe aeration device 400 (refer, for example, to the frame 11 depicted inFIG. 1). In these circumstances, the timing device 401 may be adjustedfrom a first position where the key member 403 is fitted into a firstkey slot to a second position where the key member 403 is fitted into asecond key slot. In alternative embodiments, the timing device 401 maybe coupled to the actuator shaft of a pneumatic or hydraulic cylinder,servo motor, or another powered device. In such circumstances, a usermay control the pneumatic or hydraulic cylinder, servo motor, or anotherpowered device to adjust the position of the timing device 401 whileseated in a tractor or utility vehicle.

Referring now to FIG. 32, in some embodiments, the timing device 401 maybe positioned so that the tip portion 495 of the aeration tine 490initially penetrates the ground surface 340 when the epicycleorientation of the planet gear 13 a relative to the central axis 305 issubstantially at an acute angle A. Additionally, the tip portion 495 ofthe arcuate aeration tine 490 may penetrate the ground surface 440 at asubstantially vertical angle B (e.g., substantially perpendicular to theground surface 340). For example, as previously described in connectionwith FIG. 27, the tip portion 495 of the aeration tine 490 may penetratethe ground surface 440 when angle B is approximately 75 degrees toapproximately 105 degrees and may be approximately 90 degrees. In thesecircumstances, the tip portion 395 of the tine 390 may initiallypenetrate the ground surface when angle A is approximately less than 45degrees clockwise from the vertical, may be approximately 5 degrees toapproximately 40 degrees, and may be approximately 30 degrees.

Referring now to FIG. 33, in some embodiments, the timing device 401 maybe shifted to a second position, which shifts the gear system 13 andcauses the tip portion 495 of the aeration tines 490 to penetrate theground surface 440 in a forward angular orientation. In suchcircumstances, the tip portion 495 of the aeration tine 490 initiallypenetrates the ground surface 340 when the epicycle orientation of theplanet gear 13 a relative to the central axis 405 is substantially at anacute angle C. Additionally, the tip portion 495 of the arcuate aerationtine 490 may penetrate the ground surface 440 at a forward angle D. Forexample, the tip portion 495 of the aeration tine 490 may penetrate theground surface 440 when angle D is approximately 0 degrees toapproximately 70 degrees, depending upon the curvature of the aerationtine 490, the length of the aeration tine, the height of the planetarygear 13 a, and other factors. In these circumstances, the tip portion395 of the tine 390 may initially penetrate the ground surface whenangle C is approximately less than 45 degrees counter-clockwise from thevertical, may be approximately 5 degrees to approximately 40 degrees,and may be approximately 30 degrees. Accordingly, some embodiments ofthe aeration device 400 may comprise a timing device 401 that is capableof shifting the epicycle orientation of the planet gear 13 a (relativeto the central axis 405) at the point of tine penetration from a firstepicycle orientation (e.g., angle A depicted in FIG. 32) to a secondepicycle orientation (angle C depicted in FIG. 33). In particularembodiments, the difference from the first epicycle orientation to thesecond orientation may range from about less than 45 degrees clockwisefrom the vertical to about less than 45 degrees counter-clockwiseclockwise from the vertical, or from about 30 degrees clockwise from thevertical to about 30 degrees counter-clockwise clockwise from thevertical.

Various additional modifications can be advantageously made to theapparatus described above in accordance with the teachings set forthherein. For instance, the edge on the concave side of the aeration blade80 can be replaced with a blunt surface. As noted above, the aerationblades tines can be oriented as shown in the figures, or they can berotated 180 degrees about the long axis of the blade. The planetary gearset can be modified to have any desired combination of clockwise andcounter-clockwise motions of the planet gear 13 a and sun gear 13 b sothat, for instance, both the translation and rotation of the blade arein a clockwise direction. The gear ratios and sizes can be freelymodified to create pockets having different profiles and fractures. Thetines can be grouped or staggered on the tine holders in any fashiondesired. For example, the tines can be grouped in pairs or tripletsalong the tine holders. The tines can also be disposed at a anglerelative to the vertical plane defined by the pocket shown in FIGS.21-24 to accomplish a different type of soil fracturing.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A method of aerating a ground surface, comprising: penetrating aground surface with a curved tine, the curved tine having a tip portionthat is oriented substantially perpendicular to the ground surface asthe tip portion penetrates the ground surface; and imparting compoundmotions to the curved tine while the curved tine is in the groundsurface so as to form an aeration pocket in the ground surface, whereinthe compound motions include a rotational motion of the curved tineabout a tine-holder shaft axis that drives a convex cutting edge of thecurved tine to lead through and fracture soil during formation of theaeration pocket, wherein the convex cutting edge cuts through the soilwhile said rotational motion of the curved tine about the tine-holdershaft axis drives the convex cutting edge in a direction toward a towvehicle.
 2. The method of claim 1, wherein the compound motions areimparted by a planetary gear system that imparts a revolving motionabout a central axis and said rotational motion to the curved tine. 3.The method of claim 2, wherein the revolving motion is imparted bycounterclockwise movement of a planet gear and the rotational motion isimparted by clockwise movement of a planet gear.
 4. The method of claim1, wherein the curved tine simultaneously removes a soil plug proximatethe aeration pocket.
 5. The method of claim 1, wherein the tip portionis oriented in a substantially non-perpendicular direction relative tothe ground surface as the tip portion exits the ground surface.
 6. Themethod of claim 1, wherein the compound motions imparted to the curvedtine cause the tine to form a non-symmetric aeration pocket.
 7. Themethod of claim 1, wherein a blade portion of the curved tine includesthe convex edge oppositely disposed from the concave edge, and the bladeportion has a generally continuous width between opposing side surface,wherein a height between said concave and convex edges is substantiallygreater than said generally continuous width of the blade portion.
 8. Amethod of aerating a ground surface, comprising: penetrating a groundsurface with a curved tine, the curved tine having a tip portion that isoriented substantially perpendicular to the ground surface as the tipportion penetrates the ground surface, wherein a blade portion of thecurved tine further comprises a concave cutting edge and said convexcutting edge that is oppositely disposed from the concave cutting edgesuch that a height between said concave and convex cutting edges issubstantially greater than a width of the blade portion; and impartingcompound motions to the curved tine while the curved tine is in theground surface so as to form an aeration pocket in the ground surface,wherein the compound motions include a rotational motion of the curvedtine about a tine-holder shaft axis that drives a convex cutting edge ofthe curved tine to lead through and fracture soil during formation ofthe aeration pocket.
 9. The method of claim 8, wherein the convexcutting edge cuts through the soil while said rotational motion of thecurved tine about the tine-holder shaft axis drives the convex cuttingedge in a direction toward a tow vehicle.
 10. The method of claim 8,wherein the curved tine further comprises an aeration tube laterallyoffset from the tip portion.
 11. The method of claim 8, wherein thecompound motions are imparted by a planetary gear system that imparts arevolving motion about a central axis and said rotational motion to thecurved tine.
 12. The method of claim 8, wherein the tip portion isoriented in a substantially non-perpendicular direction relative to theground surface as the tip portion exits the ground surface.
 13. Themethod of claim 8, wherein the compound motions imparted to the curvedtine cause the tine to form a non-symmetric aeration pocket.
 14. A soilaeration apparatus, comprising: a tine holder member; a gear system thatimparts compound motions to the tine holding member; and at least onecurved tine mounted to the tine holding member, the curved tine having aconcave edge, a complementary convex edge, and a tip portion, the tipportion being oriented substantially perpendicular to a ground surfacewhen the tip portion approaches the ground surface, wherein the compoundmotions are imparted to the tine holding member while the curved tine isin a ground surface, and wherein the convex edge cuts through the soilwhile the curved tine is in the ground surface, wherein the convex edgecuts through the soil while a rotational motion of the curved tine aboutan axis of the tine holding member drives the convex edge toward atowing travel direction of said apparatus.
 15. The apparatus of claim14, wherein the tip portion is oriented at an angle of approximately75-degrees to approximately 105-degrees relative to the ground surfacewhen the tip portion penetrates the ground surface.
 16. The apparatus ofclaim 15, wherein the epicycle orientation of the tine holder member isan acute angle of less than 45-degrees from vertical.
 17. The apparatusof claim 14, wherein the gear system comprises a planet gear thatimparts a translational motion and rotational motion to the curved tine.18. The apparatus of claim 17, wherein the translational motion isimparted by counterclockwise movement of the planet gear and therotational motion is imparted by clockwise movement of the planet gear.19. The apparatus of claim 14, wherein the tip portion is oriented in asubstantially non-perpendicular direction relative to the ground surfacewhen the tip portion exits the ground surface.
 20. The apparatus ofclaim 14, wherein the compound motions imparted to the tine holdermember cause the curved tine to form a non-symmetric aeration pocket.21. The apparatus of claim 14, wherein a blade portion of the curvedtine includes the convex edge oppositely disposed from the concave edge,and the blade portion has a generally continuous width between opposingside surface, wherein a height between said concave and convex edges issubstantially greater than said generally continuous width of the bladeportion.
 22. A soil aeration apparatus, comprising: a tine holdermember; a gear system that imparts compound motions to the tine holdingmember; and at least one curved tine mounted to the tine holding member,the curved tine having a concave edge, a complementary convex edge, anda tip portion, the tip portion being oriented substantiallyperpendicular to a ground surface when the tip portion approaches theground surface, wherein a blade portion of the curved tine includes theconvex edge oppositely disposed from the concave edge such that a heightbetween said concave and convex edges is substantially greater than awidth of the blade portion, and wherein the compound motions areimparted to the tine holding member while the curved tine is in a groundsurface, and wherein the convex edge cuts through the soil while thecurved tine is in the ground surface.
 23. The apparatus of claim 22,wherein the compound motions include a rotational motion that drives thecurved tine to rotate about a shaft axis of the tine holding member anddrives said convex edge of the curved tine to lead through and fracturesoil during formation of an aeration pocket.
 24. The apparatus of claim23, wherein the compound motions are imparted by a planetary gear systemthat imparts a revolving motion about a central axis of said apparatusand the rotational motion that drives the curved tine to rotate about ashaft axis of the tine holding member.
 25. The apparatus of claim 22,wherein the tip portion is oriented at an angle of approximately75-degrees to approximately 105-degrees relative to the ground surfacewhen the tip portion penetrates the ground surface.
 26. The apparatus ofclaim 25, wherein the epicycle orientation of the tine holder member isan acute angle of less than 45-degrees from vertical.
 27. The apparatusof claim 22, wherein the gear system comprises a planet gear thatimparts a translational motion and rotational motion to the curved tine.28. The apparatus of claim 27, wherein the translational motion isimparted by counterclockwise movement of the planet gear and therotational motion is imparted by clockwise movement of the planet gear.29. The apparatus of claim 22, wherein the tip portion is oriented in asubstantially non-perpendicular direction relative to the ground surfacewhen the tip portion exits the ground surface.
 30. The apparatus ofclaim 22, wherein the compound motions imparted to the tine holdermember cause the curved tine to form a non-symmetric aeration pocket.31. The method of claim 11, wherein the revolving motion is imparted bycounterclockwise movement of a planet gear and the rotational motion isimparted by clockwise movement of a planet gear.
 32. The apparatus ofclaim 22, wherein the convex edge cuts through the soil while arotational motion of the curved tine about an axis of the tine holdingmember drives the convex edge toward a towing travel direction of saidapparatus.